Heart failure is a serious disease that is caused by deterioration of ventricular muscle. This deterioration ultimately reduces the ability of the heart to pump blood, causes a number of severe symptoms, and results in a high mortality rate.
Many heart failure patients have left ventricular dysfunction wherein the left ventricle is diseased while the right ventricle remains relatively healthy. Because the right and left ventricle are fluidly connected in series, both ventricles must pump the same amount of blood. Therefore with left ventricular dysfunction, the healthier right ventricle is forced to reduce its output to that of the left ventricle. The mechanism by which this occurs is a significant increase in blood pressures against which the right heart must work. Over time, this additional stress on the right ventricle can cause right ventricular dysfunction.
Various electric and pneumatic pumps have been proposed that assist failing hearts in pumping blood. Left ventricular assist devices, for example, remove blood from the left ventricle and pump into the aorta, thereby unloading the diseased left ventricle and improving cardiac output. Because the right heart is often healthy, often no assist is provided to the right ventricle. Since assist devices must put energy into pumping blood, an energy source is required. This energy source is usually electric. Reliably providing the amount of energy needed to assist the heart significantly increases the complexity of these assist devices. Power systems often include an electric pump, an internal battery, external batteries, chargers, control systems, and a skin port (for an electrical wire or vent) or transcutaneous energy transmission (TET) coils. These various components increase cost and can result in reliability and ease-of-use problems. In addition, the implantation of these components can be time consuming and difficult. Furthermore, the blood-contacting nature of many assist devices results in significant complications (e.g., stroke).
Cardiomyoplasty was an experimental procedure that attempted to achieve active heart assist without external power. The idea was to harvest muscle from other parts of the body, wrap it around the heart, and electrically activate it in synchrony with the heart. The concept has met with little success.